Microelectronic substrate assembly planarizing machines and methods of mechanical and chemical-mechanical planarization of microelectronic substrate assemblies

ABSTRACT

A plurality of planarizing machines for microelectronic substrate assemblies, and methods of mechanical and chemical-mechanical planarization of microelectronic substrate assemblies are disclosed. The planarizing machines for processing microelectronic substrate assemblies generally include a table, a pad support assembly either positioned on or in the table, and a planarizing medium coupled to the pad support assembly. The pad support assembly includes a fluid container and an elastic membrane coupled to the fluid container. The fluid container generally is a basin either that is either a separate component that is attached to the table, or a depression in the table itself. The fluid container can also be a bladder attached to the table. The membrane generally has a first surface engaging a portion of the fluid container to define a fluid chamber or cavity, and the membrane has a second surface to which the planarizing medium is attached. The planarizing medium can be a polishing pad attached directly to the second surface of the membrane, or the planarizing medium can be a polishing pad with an under-pad that is attached to the second surface of the membrane. The fluid chamber is filled with support fluid to support the elastic membrane over the fluid chamber. The support fluid can be water, glycerin, air, or other suitable fluids that support the elastic membrane in a manner that allows the membrane and the planarizing medium to freely flex inward into the fluid chamber under the influence of a mechanical force to provide at least a substantially uniform distribution of pressure across the substrate.

TECHNICAL FIELD

[0001] The present invention relates to planarizing machines formicroelectronic substrate assemblies, and methods of mechanical andchemical-mechanical planarization of microelectronic substrateassemblies.

BACKGROUND OF THE INVENTION

[0002] Mechanical and chemical-mechanical planarizing processes(collectively “CMP”) are used in the manufacturing of microelectronicdevices for forming a flat surface on semiconductor wafers, fieldemission displays (FEDs) and many other types of microelectronicsubstrate assemblies. FIG. 1 schematically illustrates a planarizingmachine 10 with a platen or table 20, a carrier assembly 30, a polishingpad 40, and a planarizing fluid 44 on the polishing pad 40. Theplanarizing machine 10 may also have an under-pad 25 attached to anupper surface 22 of the platen 20 for supporting the polishing pad 40.In many planarizing machines, a drive assembly 26 rotates (arrow A)and/or reciprocates (arrow B) the platen 20 to move the polishing pad 40during planarization.

[0003] The carrier assembly 30 controls and protects a substrate 12during planarization. The carrier assembly 30 typically has a substrateholder 32 with a backing pad 34 that holds the substrate 12 via suction,and a drive assembly 36 of the carrier assembly 30 typically rotatesand/or translates the substrate holder 32 (arrows C and D,respectively). The substrate holder 32, however, may be a weighted,free-floating disk (not shown) that slides over the polishing pad 40.

[0004] The combination of the polishing pad 40 and the planarizing fluid44 generally define a planarizing environment that mechanically and/orchemically-mechanically removes material from the surface of thesubstrate 12. The polishing pad 40 may be a conventional polishing padcomposed of a polymeric material (e.g., polyurethane) without abrasiveparticles, or it may be an abrasive polishing pad with abrasiveparticles fixedly bonded to a suspension material. In a typicalapplication, the planarizing fluid 44 may be a CMP slurry with abrasiveparticles and chemicals for use with a conventional nonabrasivepolishing pad. In other applications, the planarizing fluid 44 may be achemical solution without abrasive particles for use with an abrasivepolishing pad.

[0005] To planarize the substrate 12 with the planarizing machine 10,the carrier assembly 30 presses the substrate 12 against a planarizingsurface 42 of the polishing pad 40 in the presence of the planarizingfluid 44. The platen 20 and/or the substrate holder 32 then moverelative to one another to translate the substrate 12 across theplanarizing surface 42. As a result, the abrasive particles and/or thechemicals in the planarizing medium remove material from the surface ofthe substrate 12.

[0006] CMP processing is particularly useful in fabricating FEDs, whichare one type of flat panel display in use or proposed for use incomputers, television sets, camcorder viewfinders, and a variety ofother applications. FEDs have a base plate with a generally planaremitter substrate juxtaposed to a faceplate. FIG. 2 illustrates aportion of a conventional FED base plate 120 with a glass substrate 122,an emitter layer 130, and a number of emitters 132 formed on the emitterlayer 130. An insulator layer 140 made from a dielectric material isdisposed on the emitter layer 130, and an extraction grid 150 made frompolysilicon or a metal is disposed on the insulator layer 140. A numberof cavities 142 extend through the insulator layer 140, and a number ofholes 152 extend through the extraction grid 150. The cavities 142 andthe holes 152 are aligned with the emitters 132 to open the emitters 132to the faceplate (not shown).

[0007] Referring to FIGS. 2 and 3, the emitters 132 are grouped intodiscrete emitter sets 133 in which the bases of the emitters 132 in eachset are commonly connected. As shown in FIG. 3, for example, the emittersets 133 are configured into columns (e.g., C₁-C₂) in which theindividual emitter sets 133 in each column are commonly connected by ahigh-speed column interconnect 170. Additionally, each emitter set 133is proximate to a grid structure super adjacent to the emitters that isconfigured into rows (e.g., R₁-R₃) in which the individual gridstructures are commonly connected in each row by a high-speed rowinterconnect 160. The row interconnects 160 are generally formed on topof the extraction grid 150, and the column interconnects 170 are formedunder the extraction grid 150 on top of the emitter layer 130. It willbe appreciated that the column and row assignments were chosen forillustrative purposes.

[0008] One concern in manufacturing FEDs is that emitters in the centerof the base plate may be damaged during CMP processing because FED baseplates generally have a significant curvature or bow that makes itdifficult to uniformly remove material from the base plates. In atypical process for fabricating the base plate 120 shown in FIG. 2, anumber of conformal layers are initially deposited over the emitters132, and then the substrate assembly is planarized. For example, aconformal dielectric layer is initially deposited over the emitter layer130 and the emitters 132 to provide material for the insulator layer140. A conformal polysilicon or amorphous silicon layer is thendeposited on the insulator layer 140 to provide material for theextraction grid 150, and a conformal metal layer is deposited over thegrid layer to provide material for the row interconnects 160. Theinternal stresses in the insulator layer 140 and the extraction gridlayer 150 generally cause the base plate 120 to have a convex “bow” sothat the center of the base plate 120 has a downward curvature when itis mounted to the substrate holder of the planarizing machine.

[0009] After all of the conformal layers are deposited, the base platesub-assembly 120 is planarized by CMP processing to form a planarsurface at an elevation just above the tips of the emitters 132. CMPprocessing, however, may remove much more material from the center ofthe base plate 120 than the perimeter regions because the FED base plate120 may have a downward curvature in the substrate carrier. As a result,CMP processing may either severely damage the extraction grid and theemitter sets at the center of FED base plates, or it may not removeenough material to expose the extraction grid and the emitter sets atthe perimeter regions. The failure to accurately form the emitter setsand the extraction grid across the whole surface of the FED base platewill cause black or gray spots on the resulting FED face plate wherepixels are not illuminated. Thus, CMP processing can destroy a whole FEDeven though only a small fraction of the extraction grid and emittersets are inoperable.

[0010] Another manufacturing concern of CMP processing is that there isa significant drive to fabricate semiconductor devices on large wafersto increase the yield of IC-device fabrication, and to develop largeFEDs that can be used in computers, televisions and other large scaleapplications. The destruction of IC-devices or emitter sets during CMPprocessing, however, is particularly problematic for applications usingtwelve-inch diameter or larger substrates because the film stressesexacerbate bowing in larger substrates. For example, because the bow ina base plate with a sixteen-inch diagonal measurement is generally about150 μm and the emitters have a height of only about 1.0-2.0 μm, CMPprocessing can easily damage or destroy a large number of emitters atthe center of the substrate. It will be appreciated that similar resultsoccur to IC-devices in the center of twelve-inch diameter substrates.Thus, CMP processes are currently impeding progress in cost-effectivelymanufacturing large FEDs or semiconductor devices on largemicroelectronic substrates.

SUMMARY OF THE INVENTION

[0011] The present invention is directed toward planarizing machines formicroelectronic substrate assemblies, and methods of mechanical andchemical-mechanical planarization of microelectronic substrateassemblies. The planarizing machines for processing microelectronicsubstrate assemblies generally include a table, a pad support assemblyeither positioned on or in the table, and a planarizing medium coupledto the pad support assembly. In one aspect of the invention, the padsupport assembly includes a fluid container and an elastic membranecoupled to the fluid container. The fluid container is generally a basinthat is either an independent component separately attached to thetable, or it is a depression in the table itself. The fluid containercan also be a bladder attached to the table. The membrane generally hasa first surface engaging a portion of the fluid container to define afluid chamber or cavity, and the membrane has a second surface to whichthe planarizing medium is attached. The planarizing medium has aplanarizing surface facing away from the elastic membrane and an undersurface coupled to the second surface of the membrane. For example, theplanarizing medium can be a polishing pad and the under surface can be abackside of the polishing pad attached directly to the second surface ofthe membrane. The planarizing medium can alternatively be a polishingpad attached to an under-pad in which the under surface is a backside ofthe under-pad that is attached directly to the second surface of themembrane. The fluid chamber is filled with a support fluid to supportthe elastic membrane over the fluid chamber. The support fluid can bewater, glycerin, air, or other suitable fluids that support the elasticmembrane in a manner that allows both the membrane and the planarizingmedium to flex inward toward the fluid chamber under the influence of amechanical force.

[0012] In operation, a substrate carrier assembly presses amicroelectronic substrate assembly against a planarizing surface of theplanarizing medium, and at least one of the substrate carrier assemblyor the planarizing medium moves to translate the substrate assemblyacross the planarizing surface. As the microelectronic substrate movesacross the planarizing surface, both the planarizing surface and theunder surface of the planarizing medium flex with the elastic membranetoward the fluid chamber to conform to a curvature of themicroelectronic substrate assembly. More specifically, the planarizingmedium and the membrane flex at a local flex zone under the substrateduring planarization to provide at least a substantially uniformdistribution of pressure across the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a schematic cross-sectional view illustrating aplanarizing machine in accordance with the prior art.

[0014]FIG. 2 is a partial isometric view of a base plate of a fieldemission display in accordance with the prior art.

[0015]FIG. 3 is a schematic top plan view of the base plate of the fieldemission display of FIG. 2.

[0016]FIG. 4 is a schematic cross-sectional view illustrating aplanarizing machine in accordance with an embodiment of the invention.

[0017]FIG. 5 is a detailed cross-sectional view illustrating anembodiment of a pad support assembly for use with the planarizingmachine of FIG. 4.

[0018]FIG. 6 is a schematic cross-sectional view illustrating an aspectof the operation of the planarizing machine of FIG. 4.

[0019]FIG. 7 is a detailed cross-sectional view illustrating anotherembodiment of a pad support assembly for use with the planarizingmachine of FIG. 4.

[0020]FIG. 8 is a schematic cross-sectional view partially illustratingstill another embodiment of a pad support assembly in accordance withanother embodiment of the invention.

[0021]FIG. 9 is a schematic cross-sectional view of another planarizingmachine in accordance with another embodiment of the present invention.

[0022]FIG. 10 is a detailed cross-sectional view partially illustratingan embodiment of a pad support assembly for use with the planarizingmachine of FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention is directed toward planarizing machines andmethods for mechanical and/or chemical-mechanical planarizing ofmicroelectronic substrate assemblies. Many specific details of certainembodiments of the invention are set forth in the following description,and in FIGS. 4-10, to provide a thorough understanding of suchembodiments. One skilled in the art, however, will understand that thepresent invention may have additional embodiments, or that the inventionmay be practiced without several of the details described in thefollowing description.

[0024]FIG. 4 is a schematic cross-sectional view of a planarizingmachine 200 and a pad support assembly 250 in accordance with oneembodiment of the invention for planarizing a substrate 12 on aplanarizing medium 290. In the embodiment shown in FIG. 4, the substrate12 has a convex “bow” such that the center of the substrate 12 has adownward curvature. The features and advantages of the pad supportassembly 250 are best understood in the context of the structure andoperation of the planarizing machine 200. Thus, the general features ofthe planarizing machine 200 will be described initially.

[0025] The planarizing machine 200 can have a housing 202, an actuator204 attached to the housing 202, and a platen or table 210 coupled tothe actuator 204. The table 210 is generally a rigid panel or plate, andthe actuator 204 rotates the table 210 (arrow RI) or otherwise moves thetable 210 (not shown).

[0026] The planarizing machine 200 also has a carrier assembly 230 tohold and control the motion of the substrate 12. In one embodiment, thecarrier assembly 230 has a substrate holder 232 to pick up, hold andrelease the substrate 12 at appropriate stages of the planarizingprocess. The carrier assembly 230 may also have an arm 234 carrying adrive assembly 235 that translates along the arm 234 (arrow T). Thedrive assembly 235 has an actuator 236 with a drive shaft 237 coupled tothe substrate holder 232. The substrate holder 232 generally has a backsurface 238 and a retaining ring 239 depending from the back surface238.

[0027] In the general operation of the carrier assembly 230, themicroelectronic substrate assembly 12 is mounted within the retainingring 239 of the substrate holder 232. When the substrate 12 has asignificant bow, a backside 14 of the substrate 12 is spaced apart fromthe back surface 238 of the substrate holder 232 such that the substrate12 has a convex curvature with respect to the substrate holder 232. Itwill be appreciated that the curvature of the substrate 12 illustratedin FIG. 4 is greatly exaggerated for the purposes of illustration. Ingeneral, a twelve-inch or sixteen-inch substrate may have a bow ofapproximately 10-350 μm.

[0028]FIG. 5 is a cross-sectional view illustrating one embodiment ofthe pad support assembly 250 on the table 210 in greater detail.Referring to FIGS. 4 and 5 together, the pad support assembly 250generally has a fluid container 260 in the table 210 and an elasticmembrane 270 coupled to the fluid container 260. The fluid container 260can be a basin with a bottom section 262 and a sidewall 264 projectingfrom the bottom section 262. The sidewall 264 terminates at a rim 266that contacts a perimeter portion of the elastic membrane 270. In theparticular embodiment of the fluid container 260 shown in FIGS. 4 and 5,the bottom section 262 and the sidewall 264 are integral components ofthe table 210 such that the basin is defined by a depression in thetable 210. As explained in more detail below, other embodiments of thefluid container can be individual components that are separatelyattached to the top of a flat table.

[0029] The elastic membrane 270 and the fluid container 260 define acavity or fluid chamber 267 in the pad support assembly 250. The elasticmembrane 270, more specifically, has a first surface 272 facing thecavity 267, and the membrane 270 has a second surface 274 facing awayfrom the cavity 267. The elastic membrane 270 is preferably anon-perforated highly elastic sheet that can be stretched across thefluid chamber 267. The elastic membrane 270 is preferably stretchedacross the fluid chamber 267 to be fairly taut when a substrate isdisengaged from the planarizing medium 290, and yet the elastic membrane270 should have sufficient flexibility and resiliency to flex inwardinto the fluid chamber 267 when a substrate engages the planarizingmedium 290. The membrane 270, for example, can be a non-perforatedrubber sheet having a thickness of approximately 0.010-0.250 inches. Theelastic membrane 270 may also be another type of suitable highlyflexible, elastic sheet.

[0030] The first surface 272 of the membrane 270 is preferably sealed tothe lip 266 of the fluid container 260 so that a support fluid 278 canfill the fluid chamber 267. The elastic membrane 270, for example, canbe attached to the rim 266 of the fluid container 260 by a retainingmember 280. In one embodiment, the retaining member 280 is a clamp-ringwith a plurality of holes that receive a plurality of fasteners 284. Thesidewall 264 of the fluid container 260 can accordingly have a pluralityof corresponding holes 269 to receive a shaft portion of the fasteners284. The fasteners 284 preferably threadably engage the holes 269 toclamp and seal a perimeter portion of the first surface 272 of theelastic member 270 to the lip 266 of the fluid container 260.Additionally, because the elastic membrane 270 is a non-perforated sheetand the retaining member 280 seals the membrane 270 to the rim 266, thesupport fluid 278 can be pressurized within the cavity 267. Topressurize the support fluid 278, the fluid container 260 preferablyalso includes a feed line 286 with a valve 288. The feed line 286 can beconnected to a pressurized source (not shown) of support fluid 278 tofill the cavity 267 with the support fluid 278 at a desired pressure.The support fluid 278 is either water, glycerin, air or other suitablefluids.

[0031] The elastic membrane 270 supports the planarizing medium 290 onthe second surface 274 of the membrane 270. The planarizing medium 290can be a flexible, elastic polishing pad, or the planarizing medium 290can be a combination of a polishing pad attached to an under-pad. Whenthe planarizing medium 290 is solely a polishing pad, the polishing padis preferably attached directly to the second surface 274 of themembrane 270. Similarly, when the planarizing medium 290 includes apolishing pad attached to an under-pad, the under-pad is preferablyattached to the second surface 274 of the membrane 270. The planarizingmedium 290 generally has a thickness of approximately 0.010-0.100 inchesdepending upon the type of polishing pad and the amount of wear.Suitable polishing pads that can be used for the planarizing medium arethe IC-60, IC-1000, or Suba-4 manufactured by Rodel Corporation ofNewark, Del. Other suitable polishing pads, however, can also be used.

[0032]FIG. 6 is a schematic cross-sectional view illustrating oneembodiment of a method for operating the planarizing machine 200 toplanarize the substrate 12. The fluid chamber 267 of the fluid container260 is initially filled with the support fluid 278 by opening the valve288 and injecting the support fluid 278 through the feed line 286. Thepressure of the support fluid 278 within the cavity 267 is preferablycontrolled to support the elastic membrane 270 and the planarizingmedium 290 to be substantially planar. The pressure within the cavity267, however, may be set so that the elastic membrane 270 and theplanarizing medium 290 are either slightly convex or concave withrespect to the bottom section 262 of the fluid container 260. Once thedesired pressure of the support fluid 278 is achieved to configure theelastic membrane 270 and the planarizing medium 290 in a desiredconfiguration, a front face 15 of the wafer 12 is planarized against theplanarizing medium 290.

[0033] To planarize the wafer 12, the carrier assembly 230 moves thesubstrate holder 232 with respect to the planarizing medium 290 whilepressing the front face 15 of the substrate 12 against the planarizingsurface 292 of the planarizing medium 290. The carrier assembly 230 mayalso rotate the substrate holder 232 to spin the wafer 12, and theactuator 204 may rotate the table 210. As the carrier assembly 230presses the substrate 12 against the planarizing surface 292, theplanarizing medium 290 and the elastic membrane 270 flex together in alocal flex zone 276 under the substrate 12. The local flex zone 276 isaccordingly defined by the portion of the elastic membrane 270 and theplanarizing medium 290 under the substrate 12 at any given moment duringthe planarizing process. The elastic membrane 270 and the planarizingmedium 290 flex in the local flex zone 276 to conform to the globalcurvature of the substrate 12. Additionally, because the membrane 270 iselastic, the areas of the membrane 270 and the planarizing medium 290that are not proximate to the substrate 12 return to an originalelevation and curvature with respect to the bottom section 262 of thefluid container 260. The pressure of the support fluid 278 and thetension of the membrane 270, therefore, control the extent of flexion inthe local flex zone 276 so that the planarizing surface 292 at leastsubstantially conforms to the curvature of the front face 15 of thesubstrate 12.

[0034] The planarizing machine 200 illustrated in FIGS. 4-6 is expectedto enhance the planarity of a planarized surface on a substrate with acurved or bowed front face. As described above with respect to thebackground of the invention section, conventional planarizing processestend to over-polish the center region of a bowed substrate. For example,even conventional processes that use compressible polishing pads andbacking pads on a rigid or otherwise inflexible support surface willoften over polish the center region of a bowed substrate because thepolishing pad and the backing pad cannot compress enough to conform tothe large extent of curvature of a large substrate. Conventionalplanarizing techniques with compressible pads supported by rigid ornon-flexible support surfaces, therefore, apply much higher pressures tothe central region of a large substrate than the perimeter regionsbecause the pads are not sufficiently compressible to readily conform tothe curvature of such large substrates. Unlike conventional processes,the embodiment of the pad support assembly 250 provides an elasticmembrane 270 and a pressurized support fluid 278 to support theplanarizing medium 290 in a manner that allows the planarizing medium290 to readily flex in a local flex zone 276. By flexing the planarizingmedium 290 and the elastic membrane 270 together to form the local flexzone 276 under the substrate 12, the planarizing surface 292 continuallyconforms to the curvature of the front face 15 of the substrate 12. Thepad support assembly 250 is accordingly expected to provide a relativelyuniform pressure distribution between the front face 15 of the substrate12 and the planarizing surface 292. Thus, compared to conventionalsystems that do not allow the planarizing medium 290 to readily flexunder the influence of the substrate 12, the planarizing machine 200 isexpected to reduce over polishing in the center regions of largesubstrates.

[0035]FIG. 7 is a side cross-sectional view illustrating anotherembodiment of the pad support assembly 250 for use with the planarizingmachine 200. In this embodiment, the fluid container 260 is anindependent component with a basin having a bottom section 262 and asidewall 264 that are separate from the table 210. Accordingly, thebottom section 262 of the fluid container 260 is attached to the table210 with a plurality of fasteners 265, adhesives (not shown) or othersuitable techniques. This embodiment of the pad support assembly 250 inFIG. 7 is particularly well suited for retrofitting existing platen-typeplanarization machines to planarize large microelectronic substrates orother substrates that are subject to having large curvatures.Additionally, the embodiment of the pad support assembly 250 illustratedin FIG. 7 also provides a great deal of flexibility because the padsupport assembly 250 can be removed from the table 210 to provide arigid support surface for conventional planarizing processes. Thus, asingle planarizing machine can be configured to planarize a substratewith a large curvature by attaching the pad support assembly 250 to thetable 210, or the planarizing machine can be configured to planarize arelatively flat substrate by removing the pad support assembly 250 fromthe table and attaching the planarizing medium 290 directly to the table210.

[0036]FIG. 8 is a cross-sectional view illustrating another embodimentof a pad support assembly 350 on a flat table 210 for use in connectionwith a planarizing machine. In this embodiment, the pad support assembly350 has a fluid container 360 and an elastic membrane 370 that togetherdefine an enclosed bladder. For example, the fluid container 360 canhave a bottom section 362 and a sidewall 364 projecting from the bottomsection 362. The elastic membrane 370 is either formed integrally withthe sidewall 364, or the membrane 370 is attached to the sidewall 364 todefine a fluid chamber 367. In one embodiment, for example, the bottomsection 362, the sidewall 364 and the elastic membrane 370 are formedintegrally from rubber or another flexible material. The elasticmembrane 370 is preferably much thinner than the bottom section 362 andthe sidewall 364 such that the elastic membrane 370 is highly flexible,and yet the bottom section 362 and the sidewall 364 are fairly rigid.The cavity 367 is preferably filled with a support fluid 378 that can beinjected into the cavity 367 with a needle or a valve.

[0037] The pad support assembly 350 is attached to the table 210, andthe planarizing medium 290 is attached to the pad support assembly 350.More specifically, the bottom section 362 of the pad support assembly350 is adhered or otherwise attached to the table 210, and theplanarizing medium 290 is adhered or otherwise attached to an exteriorsurface 374 of the elastic membrane 370. In operation, a carrierassembly (not shown in FIG. 8) presses a substrate (not shown in FIG. 8)against the planarizing surface 292 of the planarizing medium 290 toremove material from the substrate. The elastic membrane 370 and theplanarizing medium 290 accordingly flex under the influence of thesubstrate in a manner similar to that described above with respect tothe pad support assembly 250 shown in FIGS. 4-6. Accordingly, theelastic membrane 370 and the planarizing medium 290 arc expected toconform to the curvature of the substrate during planarization toprovide a uniform distribution of pressure between the front face of thesubstrate and the planarizing surface 292 of the planarizing medium 290.

[0038]FIG. 9 is a schematic side elevational view of another planarizingmachine 400 with another pad support assembly 450 in accordance withstill another embodiment of the invention for planarizing the substrate12. The planarizing machine 400 generally has a support table 410 and apad support assembly 450 to flexibly support an operative portion of aweb-format planarizing medium 490. Unlike platen-type planarizingmachines with circular, rotating tables (e.g., table 210 in FIG. 4), thesupport table 410 for the web-format planarizing machine 400 ispreferably a rectilinear, stationary table.

[0039] The planarizing machine 400 also has a plurality of rollers toguide, position and hold the operative portion of the planarizing medium490 over the pad support assembly 450. In one embodiment, the rollersinclude a supply roller 420, first and second idler rollers 421 a and421 b, first and second guide rollers 422 a and 422 b, and a take-uproller 423. The supply roller 420 carries an unused or pre-operativeportion of the planarizing medium 490, and the take-up roller 423carries a used or post-operative portion of the planarizing medium 490.A motor (not shown) drives at least one of the supply roller 420 and thetake-up roller 423 to sequentially advance the processing medium 490across the pad support assembly 450. As such, unused portions of theplanarizing medium 490 may be quickly substituted for worn sections toprovide a consistent surface for planarizing and/or cleaning thesubstrate 12. Moreover, the first idler roller 421 a and the first guideroller 422 a stretch the web-format planarizing medium 490 over the padsupport assembly 450 to hold the planarizing medium 490 stationaryduring planarization.

[0040] The planarizing machine 400 also has a carrier assembly 430 totranslate the substrate 12 across the planarizing medium 490. In oneembodiment, the carrier assembly 430 has a substrate holder 432 to pickup, hold and release the substrate 12 at appropriate stages of theplanarizing and finishing cycles. The carrier assembly 430 may also havea support gantry 434 carrying a drive assembly 435 that translates alongthe gantry 434 (arrow T). The drive assembly 435 generally has anactuator 436, a drive shaft 437 coupled to the actuator 436 and an arm438 projecting from the drive shaft 437. The arm 438 carries thesubstrate holder 432 via another shaft 439. In another embodiment, thedrive assembly 435 may also have another actuator (not shown) to rotatethe substrate holder 432 about an axis C-C as the actuator 436 orbitsthe substrate holder 432 about an axis B-B. One suitable planarizingmachine without the pad support assembly 450 is manufactured by EDCCorporation.

[0041]FIG. 10 is a detailed view of the embodiment of the pad supportassembly 450 for supporting the web-format planarizing medium 490 in theplanarizing machine 400. In this embodiment, the pad support assembly450 has fluid container 460 with a bottom section 462, a first sidewall464 a projecting from one side of the bottom section 462, and a secondsidewall 464 b projecting from an opposing side of the bottom section462. The sidewalls 464 a and 464 b each terminate at a lip 466 that hasan upper surface 468 and a depression 469.

[0042] The pad support assembly 450 also has an elastic membrane 470with an interior surface 472 facing the bottom section 462 to define acavity or fluid chamber 467. The elastic membrane 470 also has anexterior surface 474 to support the operating portion of the planarizingmedium 490. The elastic membrane 470 is generally clamped to the firstand second sidewalls 464 a and 464 b by first and second retainingmembers 480 a and 480 b, respectively. The retaining members 480 a and480 b each preferably have a lower surface 483 configured to correspondto the depression 469 in the lip 466 of the sidewalls 464 a and 464 b.The retaining members 480 a and 480 b can be attached to the sidewalls466 by a plurality of fasteners 484 to clamp the elastic membrane 470 tothe fluid container 460 in a manner that scals the fluid chamber 467.The depressions 469 in the lips 466 preferably receive the retainingmembers 480 a and 480 b so that the exterior surface 474 of the elasticmembrane 470 and an upper surface 485 of each retaining member 480 a and480 b are at least substantially coplanar. The pad support assembly 450accordingly has a flat surface for supporting the planarizing medium490.

[0043] In operation, the fluid chamber 467 is filled with a supportfluid 478 to further support the elastic membrane 470. Referring to FIG.9, the carrier assembly 430 moves the substrate holder 432 so that thefront face 15 of the substrate 12 presses against a planarizing surface492 of the web-format planarizing medium 490. The portion of theweb-format planarizing medium 490 and the elastic membrane 470 flex in alocal flex zone (not shown in FIG. 9) underneath the substrate 12 in amanner similar to that described above with reference to the planarizingmachine 200 illustrated in FIGS. 4-6. Additionally, because the padsupport assembly 450 has a flat surface, the planarizing medium 490 canbe advanced across the pad support assembly 450 without disruption toprovide a clean segment of the planarizing medium 490 over the padsupporting assembly 450. The planarizing machine 400, accordingly, isexpected to provide substantially similar results and advantages as theplanarizing machine 200, along with the additional advantages ofweb-format planarizing machines.

[0044] From the foregoing it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

1. A planarizing machine for processing microelectronic substrateassemblies, comprising: a table; a fluid container on the table; anelastic membrane over the fluid container, the membrane having a firstsurface engaging a portion of the fluid container to define a fluidchamber between an interior portion of the first surface of the membraneand the fluid container and a second surface facing away from the fluidchamber, and the membrane being coupled to the fluid container to flexthe first and second surfaces toward the fluid chamber; and aplanarizing medium having a planarizing surface facing away from theelastic membrane and an under surface coupled to the second surface ofthe membrane, the planarizing medium and the membrane being sufficientlyflexible to flex the planarizing and under surfaces of the planarizingmedium toward the fluid chamber in a local area under a microelectronicsubstrate pressed against the planarizing medium to provide at least asubstantially uniform pressure between the substrate and the planarizingsurface across the substrate.
 2. The planarizing machine of claim 1wherein the planarizing medium is bonded directly to the membrane, theplanarizing medium and the membrane flexing in unison in a local flexzone under the substrate.
 3. The planarizing machine of claim 2 whereinthe planarizing medium comprises a polishing pad, and the polishing padis bonded directly to the membrane.
 4. The planarizing medium of claim 2wherein the planarizing medium comprises a polishing pad coupled to anunder-pad, and the under-pad is bonded directly to the membrane.
 5. Theplanarizing machine of claim 1 wherein: the fluid container comprises abasin with a bottom section and a sidewall projecting from the bottomsection to a rim to define a cavity; the membrane comprises a rubbersheet; and the planarizing machine further comprises a retaining memberreleasably attached to the fluid container to clamp a perimeter portionof the membrane to the rim of the sidewall.
 6. The planarizing machineof claim 5 wherein the basin is an integral portion of the table, thebottom section and the sidewall of the basin forming a depression in thetable.
 7. The planarizing machine of claim 5 wherein the basin is aseparate component from the table, the bottom section of the basin beingattached to a surface of the table.
 8. The planarizing machine of claim5 wherein the planarizing medium comprises a polishing pad, thepolishing pad being bonded directly to the rubber sheet to flex togetherin unison.
 9. The planarizing machine of claim 5 wherein the planarizingmedium comprises a polishing pad coupled to an under-pad, the under-padbeing bonded directly to the rubber sheet to flex together in unison.10. The planarizing machine of claim 5 , further comprising supportfluid filling the fluid chamber to support the membrane.
 11. Theplanarizing machine of claim 10 wherein the support fluid comprisesglycerin.
 12. The planarizing machine of claim 10 wherein the supportfluid comprises liquid water.
 13. The planarizing machine of claim 10wherein the support fluid comprises air.
 14. The planarizing machine ofclaim 1 wherein fluid container is a bladder attached to the table, thebladder having a bottom section attached to the table and a sidewallprojecting from the bottom section, and the membrane being a top portionof the bladder integral with the sidewall, the bottom section, thesidewall, and the elastic membrane defining an enclosed fluid chamber inthe bladder.
 15. The planarizing machine of claim 14 wherein the elasticmembrane of the bladder is a rubber sheet.
 16. The planarizing machineof claim 15 , further comprising a support fluid in the fluid chamber tosupport the elastic membrane.
 17. The planarizing machine of claim 16wherein the support fluid comprises liquid water.
 18. The planarizingmachine of claim 16 wherein the support fluid comprises glycerin. 19.The planarizing machine of claim 16 wherein the support fluid comprisesair.
 20. A planarizing machine for planarizing microelectronicsubstrates, comprising: a table; a fluid container on the table, thefluid container having an inner surface defining a cavity and a rimaround at least a portion of the inner surface; a flexible, elasticmembrane coupled to the rim, the membrane having an interior surfacefacing the inner surface of the fluid container to define a fluidchamber, and the membrane having an exterior surface facing away fromthe fluid chamber; and a planarizing medium bonded to the exteriorsurface of the membrane, the planarizing medium and the membrane flexingtogether into the fluid chamber to at least substantially conform to acurvature of a microelectronic substrate pressed against the planarizingmedium.
 21. The planarizing machine of claim 20 wherein the planarizingmedium comprises a polishing pad, and the polishing pad is bondeddirectly to the membrane.
 22. The planarizing machine of claim 20wherein the planarizing machine comprises a polishing pad coupled to anunder-pad, and the under-pad is bonded directly to the membrane.
 23. Theplanarizing machine of claim 20 wherein the membrane comprises anon-perforated sheet.
 24. The planarizing machine of claim 23 wherein:the fluid container comprises a sidewall projecting from the table, therim being an upper edge of the sidewall, and the inner surface beingdefined by the sidewall and an upper surface of the table: the membranecomprises a rubber sheet; and the planarizing machine further comprisesa retaining member attached to the sidewall to clamp a perimeter portionof the membrane against the rim.
 25. The planarizing machine of claim 24, further comprising a support fluid in the fluid chamber, wherein thesupport fluid comprises liquid water.
 26. The planarizing machine ofclaim 24 , further comprising a support fluid in the fluid chamber,wherein the support fluid comprises glycerin.
 27. The planarizingmachine of claim 20 wherein the fluid container comprises a bladder, thebladder including a bottom section attached to the table and a sidewallprojecting from the bottom section, and wherein the membrane is attachedto the sidewall to define a fluid chamber in the bladder in a spacebetween the bottom section and the elastic membrane.
 28. The planarizingmachine of claim 27 , further comprising a support fluid in the fluidchamber, wherein the support fluid comprises liquid water.
 29. Theplanarizing machine of claim 27 , further comprising a support fluid inthe fluid chamber, wherein the support fluid comprises glycerin.
 30. Theplanarizing machine of claim 27 , further comprising a support fluid inthe fluid chamber, wherein the support fluid comprises air.
 31. Aplanarizing machine for planarizing a microelectronic substrate,comprising: a table having a surface, a sidewall projecting from thesurface to define a depression on the table, and a rim at an end of thesidewall; a non-perforated elastic membrane having an interior surfacefacing the depression and an exterior surface facing away from thedepression, and the membrane being coupled to the rim to form a sealedfluid chamber between the depression and the interior surface of themembrane; a support fluid filling the fluid chamber; and a planarizingmedium coupled to the membrane, the planarizing medium and the membraneflexing into the fluid chamber against the support fluid to at leastsubstantially conform to a curvature of a microelectronic substratepressed against the planarizing medium.
 32. The planarizing machine ofclaim 31 wherein the planarizing medium comprises a polishing pad, andthe polishing pad is bonded directly to the membrane.
 33. Theplanarizing machine of claim 31 wherein the planarizing machinecomprises a polishing pad coupled to an under-pad, and the under-pad isbonded directly to the membrane.
 34. The planarizing machine of claim 31wherein the support fluid comprises water.
 35. The planarizing machineof claim 31 wherein the support fluid comprises glycerin.
 36. Aplanarizing machine for planarizing a microelectronic substrate,comprising: a table having a surface, a sidewall projecting from thesurface to define a depression on the table, and a rim at the end of thesidewall; an elastic membrane having an interior surface facing thedepression and an exterior surface facing away from the depression, andthe membrane being coupled to the rim to form a sealed fluid chamberbetween the depression and the interior surface of the membrane; asupport fluid filling the fluid chamber; and a planarizing medium bondedto the membrane, the planarizing medium and the membrane flexing againstthe support fluid into the fluid chamber to at least substantiallyconform to a curvature of a microelectronic substrate pressed againstthe planarizing medium.
 37. The planarizing machine of claim 36 whereinthe membrane comprises a non-perforated sheet.
 38. The planarizingmachine of claim 36 wherein the planarizing medium comprises a polishingpad, and the polishing pad is bonded directly to the membrane.
 39. Theplanarizing machine of claim 36 wherein the planarizing machinecomprises a polishing pad coupled to an under-pad, and the under-pad isbonded directly to the membrane.
 40. The planarizing machine of claim 36wherein the support fluid comprises water.
 41. The planarizing machineof claim 36 wherein the support fluid comprises glycerin.
 42. Aplanarizing apparatus for use in a planarizing machine formicroelectronic devices, comprising: a pad support assembly having abottom section configured to be attached to a table of the planarizingmachine, a sidewall projecting from the bottom section, an elasticmembrane coupled to the sidewall to define an enclosed fluid chamber,the bottom section, the sidewall and the elastic membrane being anintegral component defining a bladder; a support fluid in the fluidchamber; and a planarizing medium coupled to the elastic membrane, theplanarizing medium and the elastic membrane flexing in a local flex zoneunder a substrate pressed against the planarizing medium to provide atleast a substantially uniform pressure distribution across thesubstrate.
 43. The planarizing apparatus of claim 42 wherein the supportfluid comprises water.
 44. The planarizing apparatus of claim 42 whereinthe support fluid comprises glycerin.
 45. The planarizing apparatus ofclaim 42 wherein the support fluid comprises air.
 46. In the fabricationof microelectronic substrates, a method of planarizing a microelectronicsubstrate, comprising: removing material from a surface of the substrateby contacting the substrate with a planarizing surface of a planarizingmedium and moving the substrate with respect to the planarizing surface;and flexing portions of the planarizing medium under the substrate asthe substrate moves across the planarizing medium to continuouslyconform a local flex zone on the planarizing medium to a globalcurvature across the substrate and provide at least a substantiallyuniform pressure distribution across the substrate.
 47. The method ofclaim 46 wherein the planarizing medium is bonded directly to an elasticmembrane and the elastic membrane is attached to a fluid container todefine a fluid chamber filled with a support fluid, and wherein flexingthe planarizing medium comprises flexing the local flex zone in theplanarizing medium and the elastic membrane in unison.
 48. The method ofclaim 47 , further comprising filling the fluid chamber with water. 49.The method of claim 47 , further comprising filling the fluid chamberwith glycerin.
 50. The method of claim 46 , further comprising bondingthe planarizing medium directly to a non-perforated elastic membrane,the elastic membrane being coupled to a fluid container to define afluid chamber filled with a support fluid.
 51. The method of claim 50 ,further comprising filling the fluid chamber with water.
 52. The methodof claim 51 wherein filling the fluid chamber with water comprisespressurizing the water within the fluid chamber to a pressure ofapproximately 0.25 psi to 10 psi.
 53. The method of claim 50 , furthercomprising filling the fluid chamber with a liquid having a viscositygreater than water.
 54. In the fabrication of microelectronicsubstrates, a method of planarizing a microelectronic substrate,comprising: pressing a surface of the substrate against a planarizingsurface of a planarizing medium bonded to an elastic membrane, themembrane being attached to a fluid container to define a fluid chamberfilled with a support fluid; moving at least one of the substrate or theplanarizing medium with respect to the other; and flexing portions ofthe planarizing medium and the elastic membrane in a local flex zoneunder the substrate as the substrate moves across the planarizing mediumto continuously conform the portions of the planarizing medium in thelocal flex zone to a global curvature across the substrate.
 55. Themethod of claim 54 wherein flexing the portions of the planarizingmedium comprises flexing the portions of the planarizing medium and theelastic member in the local flex zone in unison.
 56. The method of claim55 , further comprising filling the fluid chamber with water.
 57. Themethod of claim 55 , further comprising filling the fluid chamber withglycerin.
 58. The method of claim 54 , further comprising bonding theplanarizing medium directly to a non-perforated elastic membrane. 59.The method of claim 58 , further comprising filling the fluid chamberwith water.
 60. The method of claim 59 wherein filling the fluid chamberwith water comprises pressurizing the water within the fluid chamber toa pressure of approximately 0.25 psi to 10 psi.
 61. The method of claim58 , further comprising filling the fluid chamber with a fluid having aviscosity greater than water.